Certificate of correction



United States Patent "ice 3,125,531 LUBRICATING COMPOSITION Howard J.Matson, Harvey, Ill., assignor, by mesne assignments, to SinclairResearch Inc., New York, N.Y., a corporation of Delaware No Drawing.Filed Jan. 3, 1961, Ser. No. 79,968 4 Claims. (Cl. 252--54.6)

The present invention relates to novel reaction products useful assynthetic lubricant additives. Addition of the reaction products of thepresent invention to synthetic lubricants provides the lubricants withimproved extreme pressure properties.

The products of the present invention are polyesters prepared by directesterification of an alkane dicarboxylic acid with abis(chloro-4-hydroxy phenyl) alkane or by an ester interchange betweenthe ester of the dicarboxylic acid and the bis(chloro-4-hydroxy phenyl)alkane. These reactions are continued for a time sufficient to produce aproduct that is compatible, i.e. soluble, miscible or dispersible withthe synthetic fluid to which it is added. Ordinarily the polyesters areof lubricating viscosity, for instance having a kinematic viscosity at210 F. of about 5 00 to 300,000 centistokes. The reaction products ofthe present invention are added to synthetic lubricants in amountssufiicient to endow the lubricant with improved load carrying capacity,particularly as measured by the Falex extreme pressure test. Normallyabout 0.5 to 20 weight percent, preferably about 1 to weight percent ofthe polyester is employed.

The bis(chloro-4-hydroxy phenyl) alkane employed in preparing theadditive of the present invention can be illustrated by the structuralformula:

wherein R is a divalent aliphatic hydrocarbon radical of about 1 to 8carbon atoms, preferably 1 to 6 carbon atoms, straight or branchedchained, and n=1 to 4, preferably 1 to 2. The phenyl and R radicals mayalso be substituted with non-interferring groups. Suitable compoundsare, for example, dimethyl, bis(dichloro-4-hydroxy phenyl) methane;dimethyl bis(tetrachloro-4-hydroxy phenyl) methane;bis(dichlbro-4-hydroxy phenyl) ethane; bis(tetrachloro-4-hydroxy phenyl)propane; diethyl, bis(dichloro-4-hydroxy phenyl) methane; diethyl,bis(tetrachlorol-hydroxy) methane, etc.

The alkane dicarboxylic acids employed in preparing the polyesters aredicarboxylic acids of the structural formula HOOCR-COOH wherein R is adivalent hydrocarbon radical generally containing 1 to 28 carbon atomsand includes the branched and straight structures which are saturated orunsaturated. The preferred acids are the saturated alkane dicarboxylicdibasic acids containing up to about 12 carbon atoms. Such acidsinclude, for instance, succinic, adipic, suberic, azelaic, sebacic,brassic, brassylic, pentadecanedicarboxylic, etc.

When the reaction products are made by an ester interchange reaction,the esters of the above described dibasic acids are employed. The estershave the structural formula:

wherein R is as described above and R is a lower alkyl radical, i.e. of1 to 5 carbons, preferably 1 to 3 carbon atoms. The esters used arethose of the above acids and 3,l25,53l Patented Mar. 17, 1964 the loweraliphatic alcohols so that the alcohol produced in the reaction will bevolatilized under the reaction conditions. Suitable esters includemethyl sebacate, ethyl adipate, propyl azelate, isopropyl succinate,butyl sebacate, pentyl succinate, methyl brassylate and similar estersof the other dicarboxylic acids.

In preparing the reaction products of the present invention a molarratio of 0.5 to 2.0 moles of the acid or its ester per mole of thechloro bisphenol compound preferably 0.8 to 1.25 is employed; theparticularly preferred ratio being about 1:1. When the esterificationreaction is conducted between a dibasic acid and the phenol it iscontinued with concomitant boiling-off of water from the reactionmixture until the product has the desired viscosity. The temperature ofthis reaction is usually at least about 300 F. and should not be so highas to decompose the wanted product. If desired, the reaction can beconducted in the presence of a solvent, for instance an aromatichydrocarbon such as xylene, and to provide a better reaction rate Iprefer to employ an acid esterification catalyst. Many of thesecatalysts are known and include for instance hydrochloric acid, sulfuricacid, aliphatic and aromatic sulfonic acids, phosphoric acid, perchloricacid, hydrobromic acid, hydrofluoric acid and dihydroxyfluoboric acid.Other catalysts are thionyl chloride, boron trifluoride, silicontetrafluoride, the chlorides of magnesium, aluminum, iron, zinc, copperand tin and salts of mercury, silver, cobalt, nickel and cerium. In thepreferred reaction, when employing the dibasic acid, I use about 0.1 to05 weight percent of paratoluene sulfonic acid catalyst, a xylenesolvent and a temperature of about 345 to 390 F. while boiling-off waterby refluxing.

When employing the esterification or ester interchange alcoholysisreaction between the dicarboxylic acid ester and the phenol, I prefernot to use a solvent and the temperature is generally above 350 F., butnot so high as to decompose the Wanted product. Advantageously, thetemperature is in the range of about 435 to 480 F. Many ester exchangecatalysts are known and include for instance, zinc stearate, aluminumstearate, dibutyl-tin oxide, titanium tetraesters of lower aliphaticalcohols, sodium acid sulfate, sulfuric, hydrochloric and sulfonicacids, aluminum alkoxides, sodium methyl carbonate. Also, thesecatalysts are exemplified by the alkali metal and alkaline earth metalalkoxides, hydroxides and carbonates.

In both the direct and ester interchange reactions the reaction iscontinued with concomitant boiling-off of water (direct esterification)or alcohol (ester interchange) from the reaction mixture until thepolyester has a kinematic viscosity of at least about 500 centistokes at210 F. The polymerization should not be continued for so long a periodthat a product insoluble in synthetic fluids results. The polyesteradditive ordinarily will have a viscosity of about 500 to 25,000centistokes at 210 F., preferably about 750 to 1500 centistokes. Whenthe heating is stopped a capping alcohol can be added to the reactionmixture to tie up any remaining acid. Suitable capping alcohols are, forexample, low molecular Weight alkanols of up to about 20 carbon atoms,preferably the lower normal alkanols of 1 to 5 carbon atoms. Othermaterials such as alkylene oxides may be used instead of the alkanols.

The synthetic fluids to which the reaction products of the presentinvention are added are ester-based oils of lubricating viscosity andmay be, for instance, a simple ester or compounds having multiple estergroupings such as complex esters, polyesters, or diesters. These estersare made from monoand polyhydroxy aliphatic alcohols and aliphaticcarboxylic acids, frequently of about 4 to 12 carbon atoms, aliphaticincluding cycloaliphatic. The term alkanol is used to designate themonoand polyhydroxy alcohols while the term alkane carboxylic aciddenotes the monoand polycarboxylic acids. The reaction product of amonohydroxy alcohol and a monocarboxylic acid is usually considered tobe a simple ester. A diester is usually considered to be the reactionproduct of 1 mole of a carboxylic acid, say of 6 to 10 carbon atoms,with 2 moles of a monohydric alcohol or of 1 mole of a glycol of 4 to 10carbon atoms with two moles of a monocarboxylic acid of 4 to 10 carbonatoms. The diesters frequently contain from 20 to 40 carbon atoms. Onecomplex ester is of the type X--YZY-X in which X represents a monohydricalcohol residue, Y represents a dicarboxylic acid residue and Zrepresents a glycol residue and the linkages are ester linkages. Thoseesters, wherein X represents a monoacid residue, Y represents a glycolresidue and Z represents a dibasic acid residue are also considered tobe complex esters. complex esters often have 30 to 50 carbon atoms.Polyestcrs, or polyester bright stocks, can be prepared by directesterification of dibasic acids with glycols in about equimolarquantities. The polyesterification reaction is usually continued untilthe product has a kinematic viscosity from about 15 to 200 centistokesat 210 F., and preferably 40 to 130 centistokes at 210 F.

Although each of these products in itself is useful as a lubricant, theyare particularly useful when added or blended with each other insynthetic lubricant compositions. These esters and blends have beenfound to be especially adaptable to the conditions to which turbineengines are exposed, since they can be formulated to give a desirablecombination of high flash point, low pour point, and high viscosity atelevated temperatures, and need contain no additives which might leave aresidue upon volatilization. In addition, many complex esters have showngood stability to shear. Natural esters, such as castor oil may also beincluded in the blends, as may be up to about 1 percent or more byweight of a foam inhibitor such as a methyl silicone polymer or otheradditivcs to provide a particular characteristic, for instance, extremepressure or load carrying agents, corrosion inhibitors, etc. can beadded.

Typical synthetic lubricants may be formulated essentially from a majoramount (about 60-85%) of a complex ester and a minor amount (about15-40%) of a diester, by stirring together a quantity of diester andcomplex ester at an elevated temperature, altering the proportions ofeach component until the desired viscosity is reached. Polyesters can beemployed to thicken diester base stocks to increase the load carryingcapacity of the base diester oil. The polyester will generally notcomprise more than about 50 weight percent of the blend, preferablyabout 20 to 35 weight percent. Usually the amount of the polyesteremployed in any blend would be at least about percent, and the majorityof the lubricant is a diester. Other polymers such as acryloids may beadded as thickeners to the esters, generally the simple esters such asthe above diesters, to obtain a base oil of desired viscosity. Theacryloids are polymers of mixed C to C esters of methacrylic acid having10,000 to 20,000 molecular weight. Advantageously the final lubricatingoil composition would have a maximum viscosity at 40 F. of about 13,000centistokes and a minimum viscosity of about 7.5 centistokes at 210 F.

The monohydric alcohols employed in these esters usually contain lessthan about 20 carbon atoms and are generally aliphatic. Preferably thealcohol contains up to about 12 carbon atoms. Useful aliphatic alcoholsinclude butyl, hexyl, methyl, iso-octyl and dodecyl alcohols, C oxoalcohols and octadecyl alcohols. C to C branched chain primary alcoholsare frequently used to The improve the low temperature viscosity of thefinished lubricant composition. Alcohols usch as n-decanol, 2-ethylhexanol, oxo alcohols, prepared by the reaction of carbon monoxideand hydrogen upon the olefins obtainable from petroleum products such asdiisobutylene and C olefins, ether alcohols such as butyl carbitol,tripropylene glycol monoisopropyl ether, dipropylene glycolmonoisopropyl ether, and products such as Tergitol 3A3, which has theformula C H O(CH CI-I O) H, are suitable alcohols for use to produce thedesired lubricant. If the alcohol has no hydrogens on the beta carbonatoms, it is neo-structured; and esters of such alcohols are oftenpreferred. In particular, the neo-C alcohol2,2,4-trimethylpentanol-l-gives lubricating diesters or complex esters suitable forblending with diesters to produce lubricants which meet stringentviscosity requirements. isooctanol and isodecanol are alcohol mixturesmade by the 0x0 process from C -C copolymer heptenes. The cut whichmakes up isooctanol usually contains about 17% 3,4-dimethylhexanol; 29%3,5-dimethylhexanol; 25% 4,5-dimethylhexanol; 1.4% 5,5-dimethylhexanol;16% of a mixture of 3-methylheptanol and 5-ethylheptanol; 2.3%4-ethylhexanol; 4.3% a-alltyl alkanols and 5% other materials.

Generally, the glycols contain from about 4 to 12 carbon atoms; however,if desired they could contain a greater number. Among the specificglycols which can be employed are 2-ethyl-1,3,hexanediol,2-propyl-3,3-heptanediol, Z-methyl-1,3-pentanediol,2-butyl-1,3-butanedio1, 2,4-diphenyl-1,3-butanediol, and 2,4-dimesityl1,3 butanediol. In addition to these glycols, other glycols may be used,for instance, where the alltylene radical contains 2 to 4 carbon atomssuch as diethylene glycol, dipropylene glycol and other glycols up to1000 to 2000 molecular weight. The most popular glycols for themanufacture of ester lubricants appear to be polypropylene glycolshaving a molecular weight of about -300 and Z-ethyl hexanediol. The2,2-dimethyl glycols, such as neopentyl glycol have been shown to impartheat stability to the final blends. Minor amounts of other glycols orother materials can be present as long as the desired properties of theproduct are not unduly deleteriously affected.

Aside from glycols, the esters may be made from polyhydric alcohols ofmore than two hydroxyl groups, e.g. triand tetrahydroxy aliphaticalcohols having about 4 to 12 carbon atoms, preferably about 5 to 8carbon atoms; for instance pentaerythritol, trimethylolpropane and thelike. Particularly suitable ester base oils are formed when thesealcohols are reacted with monocarboxylic acids having about 4 to 12carbon atoms, preferably 4 to 9 carbon atoms. It is preferred that thereaction be con ducted so as to substantially completely esterify theacids.

One group of monocarboxylic acids includes those of 8 to 24 carbon atomssuch as stearic, lauric, etc. The carboxylic acids employed in makingester lubricants will often contain from about 4 to 12 carbon atoms.Suitable acids are described in U.S. Patent No. 2,575,195 and includethe aliphatic dibasic acids of branched or straight chain structureswhich are saturated or unsaturated. The preferred acids are thesaturated aliphatic carboxylic acids containing not more than about 12carbon atoms, and mixtures of these acids. Such acids include succinic,adipic, suberic, azelaic and sebacic acids and isosebacic acid which isa mixture of a-ethyl suberic acid, u,u'-diethyl adipic acid and sebacicacid. This composite of acids is attractive from the viewpoint ofeconomy and availability since it is made from petroleum hydrocarbonsrather than the natural oils and fats which are used in the manufactureof many other dicarboxylic acids, which natural oils and fats arefrequently in short supply. The preferred dibasic acids are sebacic andazelaic or mixtures thereof. Minor amounts of adipic used with a majoramount Olf sebacic may also be used with advantage.

Various useful ester base oils are disclosed in US Patents Nos.2,499,983; 2,499,984; 2,575,195; 2,575,196; 2,703,811; 2,703,724 and2,723,286. Generally, the synthetic base oils consist essentially ofcarbon, hydrogen and oxygen, i.e. the essential nuclear chemicalstructure is formed by these elements alone. However, these oils may besubstituted with other elements such as halogens, e.g. chlorine andfluorine. Some representative components of ester lubricants are ethylpalmitate, ethyl stearate, di-(2-ethylhexyl) sebacate, ethylene glycoldilaurate, di-(Z-ethylhexyl) phthalate, di-(1,3-methylbutyl) ad-ipate,di-(Z-ethylbutyl) adipate, di-( l-ethylpropyl) adipate, diethyl oxylate,glycerol trim-octoate, di-cyclohexyl adipate, di-(undecyl) sebacate,tetraethylene glycoldi-(Z-ethylene hexoate), di-cellosolve phthalate,butyl phthallyl butyl glycolate, di-n-hexyl rfumarate polymer, dibenzylsebacate, and diethylene glycol bis (Z-n-butoxy ethyl carbonate).Z-ethylhexyl-adipate-neopentyl glycyladipate-Z-ethylhexyl, is arepresentative complex ester. Generally, these synthetic esterlubricants have a viscosity ranging from light to heavy oils, e.g. about50 SUS at 100 F. to 250 SUS at 210 F., and preferably 30 to 150 SUS at210 F.

The esters are manufactured, in general, by mere reaction of thealcoholic and acidic constituents, although simple esters may beconverted to longer chain components by transesterification. Theconstituents, in the proportions suitable for giving the desired ester,are reacted preferably in the presence of a catalyst and solvent orwater entraining agent to insure maintenance of the liquid state duringthe reaction. Aromatic hydrocarbons such as xylene or toluene haveproven satisfactory as solvents. The choice of solvent influences thechoice of temperature at Which the esterification is conducted; forinstance, when toluene is used, a temperature of 140 C. is recommended;with xylene, temperatures up to about 195 C. may be used. ,To provide abetter reaction rate an acid esterification catalyst is often used. Manyof these catalysts are known and include, [for instance, HCl, H 80NaHSOr, aliphatic and aromatic sulfonic acids, phosphoric acid,hydrobrornic acid, HF and dihydroxyfluoboric acid. Other catalysts arethionyl chloride, boron trifiuoride and silicon tetrafluoride. Titaniumesters also make valuable esterification and transesterificationcatalysts.

In a preferred react-ion, about 0.5 to about 1 weight percent, oradvantageously, 0.2 to 0.5% of the catalyst is used with a xylenesolvent at a temperature of 165 to 200 C. while refluxing water. Thetemperatures of the reaction must be sufiicient to remove the water fromthe esterification mass as it is formed. This temperature is usually atleast about 140 C. but not so high as to decompose the wanted product.The highest temperature needed for the reaction will probably be about200 C., preferably not over about 175 C. The pressure is convenientlyabout atmospheric. Although reduced pressure or superatmosphenicpressure could be utilized, there is usually no necessity to use reducedpressures, as the temperatures required at atmospheric pressure toremove the water formed do not usually unduly degrade the product.

If desired other additives may be added to the synthetic lubricantcompositions of the present invention to improve other characteristicsof the lubricant so long as they do not deleteriously affect thefunctional properties of the composition. Such additives are, forinstance, antioxidants, viscosity index improvers, corrosion inhibitors,other extreme pressure agents, etc.

The following examples are included to further illustrate the reactionproducts of the present invention and the properties of lubricantscontaining them but are not to be considered limiting.

EXAMPLE I 50 grams of tetrachlorobisphenol (0.13 mol.) and 31 grams ofsebacic acid (0.13 mol. plus 20% excess), 0.5 gram of toluene sulfonicacid, and 250 ml. of toluene d were placed in a 1 liter 3-neck flaskequipped with thermowell, water trap and condenser, and stirrer. Afterabout 8 hours of reflux at C. pot temperature, a few drops of cone. H504 were added. Reflux was continued for 23 hours, collecting :a totalof 3.8 ml. water of reaction, or about 81% of theory. 40 grams ofZ-ethylhexyl alcohol were then added, and refluxed for 6 hours toesterify any unreacted sebacic acid. Solvent and excess alcohol wereremoved by vacuum stripping at 150 C. The recovered product wasdesignated product A and analyzed 17.8% chlorine (theoretical 19% basedon dilution).

EXAMPLE II 222 grams of 2,5-dichlorobisphenol (0.75 mol.), 151 gramssebacic acid (0.75 mol.), 1 gram of NaHSO and 500 ml. of toluene werecombined in a 2 liter, 3-neck flask equipped with stirrer, water trapand condenser, and thermowell. After about 6 hours reflux at 150 C.,since no water or reaction was evolved, 1.5 grams of p-toluenesulfonicacid was added to the reaction mixture. After about 45 hours of reflux,17 m1. of water or about 63% of theory were collected. 100 grams of2-ethylhexanol were then added and refluxed for 16 hours, collecting anadditional 10 ml. of water, equal to theory. The solvent and excessalcohol were removed by stripping under vacuum to C. The recoveredproduct was designated product B and analyzed 12.2% chlorine(theoretical 12.6% based on dilution).

Oil blends of Plexol 201-1 (di-Z-ethylhexyl sebacate having 0.02% freesebacic acid) and various concentrations of the polyesters of Examples Iand II were prepared and tested for load-carrying ability in the Falexlubricant testing apparatus and the SAE extreme pressure testingmachine. Plexol 201-] without the additive was also tested. The resultsare shown in Table I below.

For comparative purposes various concentrations of the diester andpolyesters prepared in accordance with Examples III to VI below inPlexol 201-] were also tested.

EXAMPLE III Dibutyl chlorendate was prepared by refluxing 371 grams (1mol.) of chlorendic anhydride, 300 grams of n-butyl alcohol (4 mols.)and 2.5 grams of p-toluenesulfonic acid, until the theoretical amount ofwater (18 ml.) had been collected in a water trap. The excess water wasthen removed under vacuum to a pot temperature of C. The product wasdesignated product D and analyzed 42% chlorine (theoretical 42.5%).

EXAMPLE IV EXAMPLE V This product was prepared by reacting chlorendicanhydride with polyethylene glycol chloride in accordance with themethod of Example IV. It was topped to 150 C./ 15 mm. The productanalyzed 37.2% chlorine (theoretical 38.7) and was designated Product I.

EXAMPLE VI This product was prepared by reacting sebacic acid withpolyethylene glycol chloride (having an average molecular weight of 210)in accordance with the method of Example IV. It was topped to 150 C./10mm. and analyzed 10.9% chlorine (12.1% theoretical). It was designatedProduct I.

The results of the tests on oil blends containing the products ofExamples 111 to V1 are also shown in Table I below for purposes ofcomparison:

c; l to 8 carbon atoms and :2 equals 1 to 4, the molar ratio of saidselected acid and ester to said chlorobisphenol reacted being 0.5 to2:1.

Table I Viscosity, cst., at Falcx (lbs.) SAE 210 F. Conc Sate AdditiveReactants Class per- Load cent (lbs.) Actual Extrap b Pass Fail None r1,250 1,500 108 A tetrachloro-bis phcnol+scbaeic acid (17.8% C1).Polycster 722 12,000 i 2 0. 5 1500 1, 750 336 B dichlorobisphcnolsebacic acid (12.2% C) 40 1, 000 2.0 4, 500+ None 358 5. 0 4, 500+ None410 0. 5 500 1, 750 328 D butyl alcohol ehlorendic acid (42% C1) Dicster8 8 1, 500 1, 750 386 436 H lauryl alcohol ehlorendic acid (27.8% o1 d011 11 I P 379535? (glycol chloride chlorcndic do 28 a g aci J Polyeggygnglycol chloride sebaeic acid s. do 9 9 10. O l). 1 y

* Plcxol 201-1 which is di-2-ethylhexyl sebacate sebacie acid (free).

b Actual viseosity-with esters A-B and I there was unreacted acid andviscosity was on this product and extrapolated for ester viscosity.

The data of Table I demonstrates the improved load carrying capacity ofsynthetic lubricants containing the polyesters of the present invention(A or B) when compared to the load carrying capacity of the syntheticoil alone. With respect to the diesters tested, the results show thatwhile the SAE load value of lubricants containing those additives may becomparable to the SAE load values provided by the additives of thepresent invention, the Falex test values are far inferior. Thedifierence is even more significant when considering the fact that 3 ofthe 4 comparative ester products tested contained a much higherpercentage of chlorine.

I claim:

1. A lubricant composition consisting essentially of an ester-basedsynthetic fluid of lubricating viscosity, said ester-based fluid beingof an alkanol of 4 to 12 carbon atoms and an alkane carboxylic acid of 4to 12 carbon atoms and a minor amount suificient to improve loadcarryingcapacity of said fluid of a base oil-compatible polyester reactionproduct of a material selected from the group consisting of adicarboxylic acid having the structural formula:

and an ester having the structural formula:

ROOCRCOOR' wherein R in said formulae is an aliphatic saturated divalenthydrocarbon radical of 1 to 28 carbon atoms and R is a lower alkylradical of 1 to 5 carbon atoms, and a chlorobisphenol having thestructural formula:

wherein R is a divalent aliphatic hydrocarbon radical of 2. Thecomposition of claim 1 wherein R in the structural formula of said esterand acid is a saturated divalent hydrocarbon of up to 12 carbon atoms.

3. The composition of claim 1 wherein the amount of the polyesterreaction product is about 0.5 to 20 weight percent.

4. A lubricant composition consisting essentially of an ester-basedsynthetic fluid of lubricating viscosity, said ester-based fluid beingof an alkanol of 4 to 12 carbon atoms and an alkane carboxylic acid of 4to 12 carbon atoms and about 0.5 to 20 Weight percent of a baseoilcompatible polyester reaction product of a dicarboxylic acid havingthe structural formula:

HOOC-R-COOH wherein R is an aliphatic divalent hydrocarbon radical of upto 12 carbon atoms and a chlorobisphenol having the structural formula:

wherein R is a saturated divalent aliphatic hydrocarbon radical of 1 to6 carbon atoms and n equals 1 to 2, the

mole ratio of said acid to said chlorobisphenol reacted eing about 0.5to 2.0: 1.

References Cited in the file of this patent UNITED STATES PATENTS2,058,394 Arvin Oct. 27, 1936 2,147,547 Reiff et al Feb. 14, 19392,255,085 Prutton et al Sept. 9, 1941 2,460,035 Rogers et al Jan. 25,1949 2,569,122 Adelson Sept. 25, 1951 2,971,913 David et al Feb. 14,1961 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,,125,531 March 1? 1964 Howard J, Matson It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below.

Column I line 52 strike out 'saturatedM and insert the same beforedivalentM in line 6O same column "Ia Signed and s ealed this 10th day ofNovember 1964,

(SEAL) Altest:

ERNEST W. SWIDER' EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

1. A LUBRICANT COMPOSITION CONSISTING ESSENTIALLY OF AN ESTER-BASEDSYTEHTIC FLUID OF LUBRICATING VISCOSITY, SAID ESTER-BASED FLUID BEING OFAN ALKANOL OF 4 TO 12 CARBON ATOMS AND AN ALKANE CARBOXYLIC ACID L OF 4TO 12 CARBON ATOMS AND A MINOR AMOUNT SUFFICIENT TO IMPROVE LOADCARRYINGCAPACITY OF SAID FLUID OF A BASE OIL-COMPATIBLE POLYESTER REACTIONPRODUCT OF A MATERIAL SELECTED FROM THE GROUP CONSISTING OF ADICARBOXYLIC ACID HAVING THE STRUCTURAL FORMULA: